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Conduction system of the heart
Conduction system of the heart

Wolff-Parkinson-White syndrome
Definition:
This syndrome involves episodes of rapid heart rate (tachycardia) caused by abnormal electrical pathways (circuits) in the heart.

Alternative Names:
Preexcitation syndrome; WPW

Causes, incidence, and risk factors:

Normally, the electrical signals which coordinate heartbeat travel through the atria (the top two chambers of the heart) to the ventricles (the bottom two chambers). These signals travel through the atrioventricular (AV) node, which is the electrical pathway connecting the two portions.

In people with Wolff-Parkinson-White syndrome, there is an extra (accessory) atrioventricular conduction pathway. This extra pathway bypasses the normal conduction delay of the AV node, and it may cause a form of "supraventricular tachycardia."

This is a rapid heart rate initiated above the ventricles. The type of supraventricular tachycardia experienced by people with Wolff-Parkinson-White syndrome is called "re-entry." The extra-electrical pathway in Wolff-Parkinson-White can often be located precisely.

Wolff-Parkinson-White occurs in approximately 4 out of 100,000 people, and is one of the most common causes of fast heart rate disorders (tachyarrhymthmias) in infants and children.

The frequency of the episodes of rapid heart rate varies from person to person. Patients with Wolff-Parkinson-White may have isolated episodes of rapid heart rate, frequent episodes (occurring once or twice a week), or they may never have symptoms. In the latter case, the condition is often discovered accidentally when a physician is reviewing an ECG requested for some other purpose.
Symptoms:
Signs and tests:
An examination during the tachyarrhythmia will reveal a heart rate greater than 150 (normal is 60 to 100 beats per minute), and blood pressure that is normal or low. If a tachyarrhythmia is not present, the physical exam may be completely normal.

Wolff-Parkinson-White syndrome may be revealed by the following tests:
  • ECG (electrocardiogram), which looks for a finding called a "delta wave"
  • continuous ambulatory monitoring (Holter monitor), which may record an episode of arrhythmia
  • EPS, an intracardiac electrophysiologic study showing the accessory pathway
Treatment:

The goal of treatment is to reduce symptoms by reducing the episodes of tachycardia (rapid heart rate).

Medication may be used to control or prevent rapid heart beating. These include adenosine, antiarrhythmics, and amiodarone. Digoxin, verapamil, and beta-blockers (other drugs commonly used to treat other types of tachycardia) can increase the frequency of tachycardia episodes for some people with Wolff-Parkinson-White.

Other treatments to stop a persistent episode of tachycardia may include electrical cardioversion (shock) or pacemakers designed to interrupt the reentry cycle. Catheter ablation may be done. This destroys the accessory pathway using a catheter (tube) inserted into the body to reach the heart.

Surgery may provide a permanent cure for Wolff-Parkinson-White. This involves ablation (destruction) of the accessory pathway using open heart surgery. Surgery may be a good approach to cure symptomatic Wolff-Parkinson-White syndrome, but it is usually only done if the patient must undergo surgery for other reasons.
Expectations (prognosis):
The outcome varies. Using a catheter to deliver radiofrequency waves to destroy the abnormal pathway usually cures Wolff-Parkinson-White. This is currently the preferred therapeutic approach to treat Wolff-Parkinson-White syndrome in the United States.
Complications:
  • reduced blood pressure caused by sustained rapid heart rate. The most severe form of tachyarrhythmia is atrial fibrillation, which may rapidly lead to shock and thus requires emergency treatment (i.e., cardioversion).
  • heart failure.
  • side effects of medications used to treat Wolff-Parkinson-White (see the specific medication).
  • complications of surgery.
Calling your health care provider:
Call your health care provider if symptoms indicating Wolff-Parkinson-White may be present, or if you have this disorder and symptoms worsen or do not improve with treatment.
Review Date: 6/4/2002
Reviewed By: Riti Patel, M.D., Department of Cardiology, Beth Israel Medical Center, New York, NY. Review provided by VeriMed Healthcare Network.
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